2016-08-03

Codd's 12 rules 科德十二定律

Codd's 12 Rules/科德十二定律/コッドの12の規則


Related to Wikipedia 2016/8/2 data
純屬資料收集,順便做一下語言學習


全關係系統十二準則

全關係系統應該完全支持關係模型的所有特徵。關係模型的奠基人埃德加·科德具體地給出了全關係系統應遵循的基本準則。

準則0 The Foundation rule
For any system that is advertised as, or claimed to be, a relational data base management system, that system must be able to manage data bases entirely through its relational capabilities.
一個關係形的關係資料庫系統必須能完全通過它的關係能力來管理資料庫。
準則1 The information rule 信息準則
All information in a relational data base is represented explicitly at the logical level and in exactly one way — by values in tables.
關係資料庫系統的所有信息都應該在邏輯一級上用表中的值這一種方法顯式的表示。
準則2 The guaranteed access rule 保證訪問準則
Each and every data (atomic value) in a relational data base is guaranteed to be logically accessible by resorting to a combination of table name, primary key value and column name.
依靠表名、主碼和列名的組合,保證能以邏輯方式訪問關係資料庫中的每個數據項。
準則3 Systematic treatment of null values 空值的系統化處理
Null values (distinct from the empty character string or a string of blank characters and distinct from zero or any other number) are supported in fully relational DBMS for representing missing information and inapplicable information in a systematic way, independent of data type.
全關係的關係資料庫系統支持空值的概念,並用系統化的方法處理空值。
準則4 Dynamic online catalog based on the relational model 基於關係模型的動態的聯機數據字典
The data base description is represented at the logical level in the same way as ordinary data, so that authorized users can apply the same relational language to its interrogation as they apply to the regular data.
資料庫的描述在邏輯級上和普通數據採用同樣的表述方式。
準則5 The comprehensive data sublanguage rule 統一的數據子語言
A relational system may support several languages and various modes of terminal use (for example, the fill-in-the-blanks mode). However, there must be at least one language whose statements are expressible, per some well-defined syntax, as character strings and that is comprehensive in supporting all of the following items:
  1. Data definition
  2. View definition
  3. Data manipulation (interactive and by program).
  4. Integrity constraints
  5. Authorization
  6. Transaction boundaries (begin, commit and rollback)
一個關係資料庫系統可以具有幾種語言和多種終端訪問方式,但必須有一種語言,它的語句可以表示為嚴格語法規定的字符串,並能全面的支持各種規則。
準則6 The view updating rule 視圖更新準則
All views that are theoretically updatable are also updatable by the system.
所有理論上可更新的視圖也應該允許由系統更新。
準則7 High-level insert, update, and delete 高階的插入、修改和刪除操作
The capability of handling a base relation or a derived relation as a single operand applies not only to the retrieval of data but also to the insertion, update and deletion of data.
系統應該對各種操作進行查詢優化。
準則8 Physical data independence 數據的物理獨立性
Application programs and terminal activities remain logically unimpaired whenever any changes are made in either storage representations or access methods.
無論資料庫的數據在存儲表示或存取方法上作任何變化,應用程式和終端活動都保持邏輯上的不變性。
準則9 Logical data independence 數據邏輯獨立性
Application programs and terminal activities remain logically unimpaired when information-preserving changes of any kind that theoretically permit unimpairment are made to the base tables.
當對基本關係進行理論上信息不受損害的任何改變時,應用程式和終端活動都保持邏輯上的不變性。
準則10 Integrity independence 數據完整的獨立性
Integrity constraints specific to a particular relational data base must be definable in the relational data sublanguage and storable in the catalog, not in the application programs.
關係資料庫的完整性約束條件必須是用資料庫語言定義並存儲在數據字典中的。
準則11 Distribution independence 分布獨立性
A relational DBMS has distribution independence.
關係資料庫系統在引入分布數據或數據重新分布時保持邏輯不變。
準則12 The nonsubversion rule 無破壞準則
If a relational system has a low-level (single-record-at-a-time) language, that low level cannot be used to subvert or bypass the integrity rules and constraints expressed in the higher level relational language (multiple-records-at-a-time).
如果一個關係資料庫系統具有一個低級語言,那麼這個低級語言不能違背或繞過完整性準則。

Ref:
http://computing.derby.ac.uk/c/codds-twelve-rules/
http://www.itworld.com/nl/db_mgr/09022002

https://ja.wikipedia.org/wiki/ゴッドの12の規則

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